Warm Water Lowers Nutrition: You Didn't Know, Right?

N.B: Important Gift for you at the end. So, slowly read and digest.

Recently, I read a news article titled "Warmer Water, Less Nutrition" written by Sonia Fernandez. The summary of it is that the nutritional value of giant kelp decreases with the rise in sea temperature. Being a scientist, I decided to learn more about the giant kelp and thought it would be nice to share some of the things I have learned. Remember that I do a course in Environmental Toxicology, and subjects as this are becoming more and more interesting.

Giant Kelp: TSP, please I need a freezer here. It's so hot and I can't feed the world

Well, you might think this is the first time you have been acquainted with the name "giant kelp", but if you are familiar with aquatic organisms, you might have been acquainted with organisms such as the algae. 

Back in freshman biology class, I would get fascinated with botanical and zoological names of organisms and often looked forward to letting someone hear me say it. It made me seem like a smart student, or maybe even smarter. 

Macrocystis pyrifera is the botanical name for giant kelp, and is the largest seaweed and the largest of all marine algae. You find its habitat in the cold, clear waters and it forms a source of habitat for several other marine organisms. While it looks like a plant, it is a brown alga and belongs to the group of eukaryotes called the Protista. Unlike most members of the group, it is not unicellular. It is the largest protist in the world.

It has a great deal of applications in aquaculture and you can find it in many food products. It is an emulsifying and binding agent used in the production of many foods and cosmetics, like ice-cream, cereal and toothpaste.

Another important phenomenon about this organism is that it grows pretty fast under suitable climatic conditions. Close to 200,000 wet tons of kelp are harvested annually in California alone where there are regulations and guidelines for safeguarding and harvesting the kelp forests. You can learn more about the management of the kelp forest here.

Remember, the giant kelp is not a plant, so it has no roots. 

How then does it obtain food nutrients? 

It obtains required nutrients directly from the water where it is connected to the rocky bottom by a holdfast. Similar to plants, it is an autotroph.  Debris of decomposing kelp sink to the depths of the ocean, serving as a source of food for deep-sea creatures.

A recent study by a graduate student researcher at UC Santa Barbara reveals that "kelp plants can’t store nitrogen for more than two weeks, so whatever’s happening around them in the water they’re going to respond to very quickly because they need a constant supply of nitrogen to grow, and to continue to reproduce.” 

A similar, yet ongoing study covered by the Santa Barbara Coastal Long Term Ecological Research for about two decades shows that nitrogen content of the giant kelp tissue reduced by about 20% with a proportional increase in carbon content.

This decrease in nutritional content is not a good sign for other dependents of the organism in the sea and extensively humans. On a mini-scale, animals like urchins that feed on kelp might waste more energy trying to satiate their nutritional needs. Urchins have the capacity to hunt for food but other consumers with less energy may only settle or starve with what they have or do not have.

The point, according to the researcher and her team, is "low-nutrition kelp could mean smaller, fewer, and malnourished beach hoppers, which would lead to less food for the shorebirds that eat them". 

The general idea, as a reiteration, is if urchins do not get the required nutrients or are malnourished, less food will be available to consumers such as fish and humans.

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If you got the gist, please provide answer(s) to One Question in the comment section below.

1.    Mention one difference and one similarity between giant kelps and green plants.

2.    What are the applications of giant kelp?

3.    What is the world's largest species of marine algae?

4.     What is the correlation between ocean-warming and nutrient depletion?

4.    What will you do to foster environmental sustainability in our changing world?

Bibliography (All Accessed Oct. 30, 2021)

Britannica. https://www.britannica.com/science/giant-kelp 

Monterey Bay Aquarium. https://www.montereybayaquarium.org/animals/animals-a-to-z/giant-kelp

National Geographic. https://www.nationalgeographic.org/photo/4kelp-holdfast/ 

National Marine Sanctuaries. https://sanctuaries.noaa.gov/visit/ecosystems/kelpdisc.html 

Oceana. https://oceana.org/marine-life/corals-and-other-invertebrates/giant-kelp 

UC Santa Barbara. https://www.news.ucsb.edu/2021/020445/warmer-water-less-nutrition